A fifth team of rescuers has joined the search for a 73-year-old woman missing from an assisted-living apartment in Perth-Andover.
Martha Kelly went for a walk Friday afternoon in the northwestern village and hasn't been seen in four days.
On Tuesday, a fifth team of search and rescue volunteers from Miramichi joined the effort.
District 10 RCMP Sgt. Marc Violette said teams are trying to cover as much ground as possible.
"The St. John River is bordered on both sides by abandoned railway beds that have been converted to multi-purpose trails. These are the trails that Mrs. Kelly used to enjoy walking on," Violette said.
"So we've had those covered by ATV, by aerial search and by ground crews. She also walked significantly on the public roads, on Highway 109, on all the streets within the village of Perth-Andover so we're covering those also."
Violette said Kelly was an avid walker and could easily have covered 20 kilometres in five hours.
He said civilian air searchers covered an area Monday from the Beechwood Dam all the way to Grand Falls, the U.S. border and Plaster Rock.
Kelly's family is keeping vigil at the command post located at her assisted living facility, Victoria Villa.
Kelly does not have major medical issues, but suffers from memory loss due to a brain aneurysm in 2002 and takes blood pressure medication.
Four ground search and rescue teams have been working the area since Saturday including Northwest, Tobique, York-Sunbury and Carleton.
A Cormorant helicopter from CFB Shearwater searched on Saturday.
On Sunday, two boats searched the St. John and the Tobique Rivers.
The provincial government has contributed a search dog from the Department of Natural Resources and members of its off-road vehicle enforcement unit.
The Perth-Andover fire department has also helped out and so has one officer from the Canadian Wildlife Service.
Members of the Canadian Air Search and Rescue Association (CASARA), covered rivers in the area on Monday including the Tobique, St. John and Aroostook.
The CASARA is a civilian organization with military training in aerial searches.